Synthesis of novel hyperbranched poly(ester-amide)s based on neutral α-amino acids via “AD + CBB′” couple-monomer approach

Authors

  • You-Mei Bao,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
    2. Graduate School of the Chinese Academy of Sciences, Changchun Branch, Changchun 130022, China
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  • Xiao-Hui Liu,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
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  • Xiu-Lan Tang,

    1. College of Environment and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
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  • Yue-Sheng Li

    Corresponding author
    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
    2. College of Environment and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
    • State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
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Abstract

A series of novel hyperbranched poly(ester-amide)s (HBPEAs) based on neutral α-amino acids have been synthesized via the “AD + CBB′” couple-monomer approach. The ABB′ intermediates were stoichiometrically formed through thio-Michael addition reaction because of reactivity differences between functional groups. Without any purification, in situ self-polycondensations of the intermediates at elevated temperature in the presence of a catalyst afforded HBPEAs with multihydroxyl end groups. The degrees of branching (DBs) of the HBPEAs were estimated to be 0.40–0.58 and 0.24–0.54 by quantitative 13C NMR with two different calculation methods, respectively, depending on polymerization conditions and structure of monomers. The influences of catalyst, temperature, and intermediate structure on the polymerization process and molecular weights as well as properties of the resultant polymers were investigated. FTIR, NMR, and DEPT-135 NMR analyses revealed the branched structure of the resultant polymers. The HBPEAs possess moderately high molecular weights with broad distributions, glass transition temperatures in the range of −25.5 to 36.5 °C, and decomposition temperatures at 10% weight loss under nitrogen and air in the regions of 243.4–289.1 °C and 231.4–265.6 °C, respectively. Among them, those derived from D,L-phenylalanine display the lowest degree of branching, whereas the highest glass transition temperature and the best thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

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